VPN is a regular part of the world right now and Opera browser is getting more and more attention these days, so to have opera vpn not going to your website is a big problem and you are missing out on a whole lot of people because of it I am sure. Not a make or break level, but even a few thousand dollars is a few thousand dollars and with this you are missing out on that.
Do you mean not allowed to use Opera browser? about VPNs I always use a VPN and don't have any problems everything is fine
I think the reason not allowed is not a VPN but because the IP is blocked some countries are not allowed to access this site
So we can assume Opera browser is using a banned IP.